Dual wall fabric with expandable height between layers

ABSTRACT

A fabric is provided in the form of two simultaneously woven opposed fabric layers disposed in closely spaced relation with integrally woven connecting strands, with the fabric being adapted for expansion of the height between layers subsequent to the weaving operation.

United States Patent Inventors Robert G. Currier Roxboro; Carl R. Fonda, Durham; John T. Hayes, Durham, allot, N.C. Appl. No. 815.076 Filed Apr. 10. 1969 Patented Sept. 7, 1971 Assignee Collins & Alkmln Corporation New York, N.Y.

DUAL WALL FABRIC WITH EXPANDABLE HEIGHT BETWEEN LAYERS 12 Claims, 10 Drawing Figs.

US. Cl 28/76 T, 1 39/410 Int. (1 D02c 27/00, D060 1/00, D03d 11/00 Field of Search 139/408-414,

[56] References Cited UNITED STATES PATENTS 2,803,268 8/1957 Maclntyre 139/410 2,848,018 8/1958 Neisler, Jr. 139/410 3,013,588 12/1961 Klingberg..... 139/410 3,224,466 12/1965 Grover 139/410 X 3,399,521 9/1968 Thoma et a1 28/76 X FOREIGN PATENTS 629,124 1/1963 Belgium 139/410 550,525 1/ 1943 Great Britain 28/76 566,507 1 1945 Great Britain 28/76 T Primary Examiner-James Kee Chi AnorneyPaul and Paul ABSTRACT: A fabric is provided in the form of two simultaneously woven opposed fabric layers disposed in closely spaced relation with integrally woven connecting strands, with the fabric being adapted for expansion of the height between layers subsequent to the weaving operation.

PATENIEUSEP H97! SHEET 1 BF 4 INVENTORS. JOHN T. HAYES BY ROBERT G. CURRIER CARL R. FONDA ATTOR NEYS PAIENIEDSEP 7m:

SHEET 2 OF 4 INVENTORS. JOHN T. HAYES ROBERT G. CURRIER BY CARL R. FONDA M PM ATTORNEYS.

PATENIEnsEP m1: 3,602,964

saw u or 4 INVENTORS.

JOHN T. HAYES ROBERT G. CURRIER CARL R. FONDA upa/2V4 ATTORNEYS.

DUAL WALL FABRIC WITH EXPANDABLE HEIGHT BETWEEN LAYERS BACKGROUND OF THE INVENTION In the past, various means have been employed for the weaving of fabrics haying plural layers or walls. In particular, in the manufacture of pile fabrics and the like, it has been commonplace to manufacture such fabric as a dual wall fabric, with opposed layers which are held together by integrally woven connecting strands, extending generally in the warp direction. As such a dual wall fabric is woven, the fabric layers are expanded by removal of the fabric over the ends of the loom gage wires, to yield a dual fabric with an expanded height between the opposed fabric layers. Inasmuch as such fabrics have often been made as a preliminary step in the manufacture of pile fabric for use in making rugs and like fabric constructions, it has been commonplace to slit the fabric between the opposed layers, by traversing the fabric layers past opposite sides of a knife or the like which would sever the connecting warp strands, thus leaving the fabric in the form of two single-pile fabric layers. An example of an expandable fabric that is later used to form a pile fabric is that disclosed in the US. Pat. to Kubicky No. 2,108,288, issued Feb. 15, 1938. It will be apparent that such constructions require the use of weft strands separate from the fabric layers, and disposed on opposite sides of the gauge wires, about which the connecting warp strands may be looped.

It is thus apparent, that in weaving operations of the type wherein the use of such separate weft strands on opposite sides of the gauges is undesirable, or wherein the traversing by a connecting warp strand of the gauge wire multiplicity of times is not desired, the expansion of the fabric has heretofore not been possible.

One novel method of weaving an expandable dual wall fabric is to weave the fabric with the fabric layers in closely spaced confronting relation, but wherein the connecting strands are weft or filling direction strands, woven between and alternately with the opposed layers, by means of the shuttle traversing the weaving machine in the usual manner, in the weft direction, with proper adjustment of the shed during the weaving operation. Such a fabric may be woven on a single shuttle loom, and results in a novel dual wall fabric which is expanded by forcibly separating the layers, although such expansion cannot take place without shortening the width (measured in the weft direction) of a given size of dual wall fabric.

Another novel method of obtaining an expandable dual wall fabric is presented herein which (1) does not require multiple crossings of the gage wires by warp direction strands between points of securement of the warp strands to fabric and (2) does not shorten the dual wall fabric in the weft direction upon expansion. In this regard, a dual wall fabric is provided having expandable connecting strands; i.e. each strand being incrementally expandable to a predetermined length. This is effected by using multiple component strands of different free lengths, the component of shorter free length being destructi ble or otherwise severable to allow the component of greater length to control the allowable spacing between opposed fabric layers.

SUMMARY OF THE INVENTION The present invention provides a novel fabric having at least two opposed fabric layers which are integrally woven with connecting threads, the threads extending either in the warp or weft direction with respect to the weaving machine, and wherein the fabric layers are provided with a preliminary spacing which is expandable.

Accordingly it is an object of this invention to provide a fabric, as well as the method of making such a fabric, wherein the length of the drop threads is increased due to the construction of the drop threads being of composite strands, with one of the strands being of greater free length than the other, and wherein the shorter of the strands is destructible or otherwise severable in a medium that does not dissolve the longer strand.

It is a further object of this invention to accomplish the above object, wherein the strand of the longer free length is wrapped about a core strand of shorter free length, and with the core being either water soluble, heat destructible, or solu ble in other chemicals.

It is another object of this invention to provide a novel expandable dual wall fabric integrally woven with connecting weft direction strands.

It is a further object of this invention to provide a novel dual wall fabric having integrally woven connecting strands, and wherein the fabric layers are capable of being expanded to provide increased height between the layers, without requiring the use of multiple connecting strand crossings of the gauges, between fastening points of the connecting strands to the layers and without requiring extraneous weft direction threads, and wherein the opposed fabric layers may be substantially of the same area both before and after expansion.

It is a further object of this invention to provide a novel method of making a dual wall fabric, wherein subsequent to weaving the fabric, the fabric is immersed in a substance in which fabric connecting strand portions are soluble.

It is yet another object of this invention to provide a novel expanded fabric constructed according to the method immediately above.

Other objects and advantages of the present invention will become readily apparent to one skilled in the art from a reading of the following brief description of the drawing of figures,

detailed description of the preferred embodiment, and the appended claims. I

IN THE DRAWINGS FIG. 1 is a side view, schematically illustrated, of apparatus adapted for the manufacture of a fabric according to this invention, wherein means are provided downstream of the loom for dissolving portions of a dual wall fabric.

FIG. 2 is a side elevational view, schematically illustrated, of a fabric of this invention, as it is removed from the weaving portion of the apparatus of this invention.

FIG. 3 is an enlarged detailed view of a portion of the fabric illustrated in FIG. 2, as defined by the boundaries of detail III of FIG. 2.

FIG. 4 is an enlarged detailed view of a portion of a connecting strand of FIG. 3, as defined by the boundaries of detail IV in FIG. 3.

FIG. 5 is a view generally similar to that of FIG. 4, but wherein the elongation of the wrapped strand component is illustrated as the core strand component of dissolving.

FIG. 6 is a view of the material of FIG. 2 in its expanded form, and wherein a portion of the dual wall fabric thus formed is illustrated in use as a containment fabric, with cement or concrete illustrated disposed between the opposed fabric layers. 1

FIG. 7 is a schematic side elevational view of an alternative apparatus for accomplishing the novel method of weaving a novel fabric of this invention.

FIGS. 8 through 10 are transverse sectional views of differently contoured dual wall fabrics in accordance with this invention, after expansion, and looking in the warp direction of the fabrics.

Referring now to the drawings in detail, reference is first made to FIG. 1, wherein there is illustrated a weaving apparatus, generally designated by the numeral 10, including harnesses collectively identified by the numeral 1 l and including individual harnesses 11a, 11b, 11c, 11d, 112 and llf, in that six harnesses as a minimum are required to weave a fabric of this type in most adaptable weaving machines. In FIG. 1 the pick 12f is indicative of a top shed, and wherein harnesses 11a and 116 make the top fabric, with harnesses 1 lb and 11d making the bottom fabric, and with harnesses 112 and 11f being operative to weave the top and bottom fabric layers together.

A reed or beater 13, a shuttle l4, and a group of rollers 15 through 18 are provided all of which cooperate to take incoming warp direction strands 12a through 12f and weave such strands with weft or stufimg direction strands such as that 20, to be delivered at the downstream side of the weaving apparatus 10, as is more fully illustrated in FIG. 2.

For. purposes of this explanation, the view of FIG. 2 will be taken as looking in the weft direction, or across the machine such that upper and lower strands 22 and 23, respectively comprise warp direction strands, which form components of their associated respective opposed fabric layers 24 and 25, of the dual wall fabric 21. The fabric 21 is illustrated as comprising the opposed fabric layers 24 and 25 closely spaced, as for example having one-eighth of an inch spacing between the layers 24 and 25. The fabric layers 24 and 25 are connected by drop warp threads 26 and 27, which connecting strands are integrally woven with each of the opposed layers 24 and 25, and which, when taken together comprise a highly flattened X- shaped configuration. This is because the spacing between the layers is only approximately one-eighth of an inch, whereas each strand 26 and 27 is approximately three-fourths of an inch long from the point where it leaves, for. example the upper fabric 24, to the point where it entersthe lower fabric 25, each strand 26 and 27 then being woven integrally with the fabric layer for approximately one-half inch, and then leaving that fabric layer for approximately another three-fourths of an inch of angular disposition as it extends toward the opposed fabric layer, for traversing the ls-inch spacing at a very gentle slope.

Inasmuch as each connecting strand 26 and 27 is substantially identical, except that one strand crosses the other, only strand 26 need be described in detail. Each strand 26 is a dual component strand, comprising a water soluble center core, 28, e.g. of polyvinyl alcohol construction, and is wrapped preferably in spiral form, with a winding 30 of nylon or like material, with the thickness of the core component 28 being approximately times the cross-sectional thickness of the wrapped strand 30.

As the dual wall fabric 21 leaves the apparatus 10, as illustrated in FIG. 1, it passes either directly or thereafter over a roll 31, around a lower portion of a rotating drum 32, and into a bath 33 of hot water, the bath 33 being contained within a suitable tank 34, and being provided with heat by a heating coil 35, the dual wall material then leaving the bath 33, to pass around the roll 36, asa dual wall fabric 37 capable of expansion to a height between layers many times the original distance between layers of the fabric 21 as for example being capable of expansion to a height between layers of approximately 4% inches, as illustrated in FIG. 6.

The fabric 21 may, if desired, first be wound onto a mandrel (not shown) and later unwound into the bath 33, if desired.

With particular reference to FIGS. 4 and 5, it will be readily understood that, upon the core 28 being dissolved, the wrapping strand 30 becomes released and capable of extension to its full length. With particular reference to FIG. 3, if the strand 26 is considered as having a securement point within the fabric layer 24 at the point designated 38, which is approximately halfway between the points where the strand 26 enters and leaves the upper layer 24, and if this strand 26 is considered to have a like lower securement point 40 within the fabric layer 25, also approximately midway between the points where the strand 26 enters and leaves the layer 25, it may be assumed that a given free length of the core component 28 of the strand portion 26 is of 1% inches long, which is the total of the Winch connection portion and one-fourth inch on each end at which the strand is engaged within its associated fabric layer. If the free length of the winding strand 30 is approximately 4 times the free length of the core strand 28, upon dissolution of the core strand 28, the free length of the winding strand 30 between securement points 38 and 40 would be approximately 5 inches. Allowing one-fourth inch to be taken up by each of the opposed layers 24 and 25, with the fabric 37 in its expanded state between securement points 38 and 40, the expanded distance between opposed layers 24 and 25 would be approximately 4% inches. Thus, it is believed that this demonstrates the degree of expansion between layers that is capable with a fabric made according to this invention.

It will be noted that the means 35 for supplying heat to the water 33 within the tank 34 may be of the steam coil type or such may comprise an electrical heating element, if desired, as long as sufficient heat is applied capable of raising the water 33 to a desired preselected temperature, generally to the boiling temperature of water.

It will further be apparent that the core 28 may be constructed of a substance which is soluble in an acid, or even a basic solution, if the same is desired, rather than being con structed of a water soluble substances. Accordingly the material forming the core 28 would be selected in conjunction with a particular bath. Still further, some core materials are destructible by heat, either separately or in conjunction with baths. The use of such materials is also contemplated. The liquid within the tank 34 would be altered accordingly, either with or without heat from the heating elements 35, as desired.

For example, with a rayon core, a solution such as 60 percent of sulfuric acid would dissolve the core, as would either a cold or hot concentrated alkaline solution. Also, the rayon core would decompose at a temperature between 300 and 464 F.

With an acetate fiber core, acetone would be a good solubility reagent, as would phenol or glacial acetic acid. A temperature in the neighborhood of 500 F. would be required to melt an acetate fiber.

A triacetate fiber would be soluble in a solution of methylene chloride. Acetone can also cause dissolution of a triacetate fiber, as can stronger acids. Triacetate does have a high melting temperature (572 F, however, so therefore destruction by means of heat alone may be impractical). Triacetate is also soluble in carbon tetrachloride and in carbon disulfide.

Nylon 6 may be melted in a bath at a temperature of 425 F and is soluble in phenol and formic acid, or in strong mineral acids. Nylon 66 has much the same characteristics of nylon 6 in this regard, but melts at a higher temperature (490 F).

Acrylic fibers are soluble in dimethyl-formamide.

Modacrylic fibers could be dissolved in a bath of warm acetone, thus being adaptable 'to destruction in a bath employing heating means, in accordance with a preferred form of this invention.

Polyester fibers are, in many instances, soluble in concentrated sulfuric acids and some phenolic compounds, and also decompose in alkalis at the boiling point of the alkalis.

Polyester fibers generally melt within the range of 482 to 554 F.

Olefin fibers are soluble in xylene and, above F in various chlorinated hydrocarbons.

Saran fibers are not generally soluble in most acids and alkalis, but melt within the range of 338 to 350 F.

Spandex fibers are soluble in a 60 percent solution of sulfuric acid, and melt above 450 F.

Also, many of the above mentioned fibers are at least partially soluble in a weak caustic solution, and therefore such may, under some circumstances, constitute a desirable bath 33 for the same.

It will be noted, that many of the fibers mentioned above become brittle when exposed to heat, as do vinyl chlorides, such that, under the pressure consonant with expansion of the dual wall fabric, such fibers would brake down in order to permit expansion. In this regard, polypropylene fibers are also reactive with heat.

It will also be apparent, from the discussion herein, and with particular reference to the preamble of this application, that the strands which connect opposed fabric layers may be provided as weft or filling direction strands, in which instance the fabric, if viewed longitudinally of the machine, rather than transversely would appear similar to the illustrations of FIGS. 2 and 3. Each connecting strand that would extend between the fabric layers could either be a multiple component strand or not, as desired. However, by using a multiple component strand with a destructible core, upon expansion of the fabric, the fabric would not shorten as measured in the weft direction.

It will further be noted that the dissolution of the core 28 of the strands 26 may take place at some location remote from the location of manufacture of the fabric 21, although it is preferable to complete the formation of the fabric 37 as an expanded fabric immediately downstream of the weaving operation of shortly thereafter. However, if for some reason it should be desirable to have expansion for example, at the site of erection, especially in those instances when the core 28 is constructed of water soluble material, the application of water or other solubility reagent may be provided by spraying, immersion, or the like of the fabric 21, to dissolve the restraining core and yield the expanded fabric 37.

It has been found to be highly desirable to use dual wall fabric such as that of 37 for containing a filling material as for example the cement material 41 illustrated in FIG. 6. In this regard the connecting strands may be of nylon or similar construction having a pronounced capability for leaching water into and out of the fill material. The filling material 41 may be pumped in slurry from between the opposed layers 24 and causing fabric expansion as the water in the concrete dissolves the fabrics cores and permitting instant expansion of the fabric to the predetermined height between layers allowed by the free length of the wrapping strands 30.

With particular reference to FIG. 7, there is illustrated another apparatus, generally designated by the numeral 50, for weaving a dual wall fabric 21, in accordance with this invention, by means of a Jacquard head loom. A warp beam 51 is provided, for delivering warp strands 53 over a back rest roll 53, passed across rails 54 and 55 and to the dobby head harnesses 56, 57, 58 and 59. Binder warp such as at 60 is delivered from a creel 61, around rollers 62 and 63, to be woven into the fabric as the warp connecting strands by using the weighted lingoe cords 64 and 65 of the Jacquard head 66. The customary reed 67 and the shuttle 68 are also utilized, with the woven fabrics 21 then passing around the breast beam 70, around rollers 71 and 72, to be wound onto a cloth beam 73. The beam 73 may, either immediately thereafter or subsequently thereto be placed on a frame 74 to be unwound, with the fabric 21 passing over a drag roll 75, into a bath 76 of water, or some other desired solution as set forth above, which has been selected in accordance with the particular construction of the connecting strands. In the bath 76, the fabric 21 travels a substantial distance by passing over the series of rolls 77, illustrated therein, to be delivered from the bath 76 over a drag roller 78. A heating means 80 is also provided for the bath 76, preferably of the steam type, wherein a plurality of steam coils 81 and 82 are provided internally of a tank 83 which houses the bath 76, with the coils 81 and 82being fed with live steam from a steam line 84.

Other uses of the dual wall fabric 37 of this invention may also be desirable, such as by coating the opposed layers 24 and 25 of the expanded fabric with a substance that is water impervious, or air impervious, for floating and like uses of various dual wall constructions. For example, it may by desirable to coat the surfaces 24 and 25 with a substance which is a semiimpervious to air for use in the formation of parachutes, parafoils and like fabric structures wherein the slightly porous nature of the coating would permit the passage of the predetermined amount of air through the fabric material, although parafoils, parachutes and the like may be constructed without such a coating, if desired.

With particular reference to FIGS. 8 through 10, wherein expanded dual wall fabrics having various configurations are illustrated, as viewed in transverse section looking in a warp direction, it will be apparent that innumerable configurations and contours are possible using the concept set forth herein of dissolving or otherwise destructing portions of the intricately woven fabric-connecting strands, to permit expansion of the fabric layers. As viewed in FIGS. 8 through 10, wherein various warp direction connecting strands are seen to be capable of expansion different amounts, it will become apparent that such degrees of expansion can be carefully controlled by selection, for example, of the particular material of the connecting strand, the relative lengths of the core and wrap, the degree of wrap of the outer strand about the core, etc.

Thus, with reference to FIGS. 8 through 10, respectively, the fabric constructions therein may be viewed, for example, as differently configured parafoils 90, 91 and 92. In the use of parafoils, it is desirable to have substantial expansion between the opposed fabric layers, for example with reference to FIG. 8 the fabric layers 93 and 94, in order to permit crosswinds to enter the foil or chute, for example in the direction of the arrow of FIG. 8, to become trapped therein, and to assist a jumper, for example a paratrooper to remain aloft for extended periods of time. Furthermore, other cross-sectional parafoil configurations, such as that of FIG. 9 may be preferable from the standpoint of enabling the user to have an increased degree of control over the movement, particularly the direction of movement of the parafoil while aloft. These examples of uses of this fabric, for containment constructions, and for parachutes and parafoils and the like are, of course, only exemplary, it being understood that various other uses are contemplated for such fabric.

Also, while particular attention has been given in this application to the application of heat and the use of water and chemical solutions as means for destroying one of the fabric components, for example the core, it will be apparent that other destruction techniques may also be utilized, such as pressure techniques. In this regard, a solvent, for example ether could be utilized under pressure which pressure would facilitate the early separation of the fabric layers. Furthermore, completely different destruction techniques are contemplated for the core of this invention, such as the use of ultrasonics as a heat generator for applying the heat spoken of herein which can be used either to melt or make brittle the core of the fabric connecting strands. Along these same lines, high intensity radio waves may also be used in combination with a core having low energy breakdown levels, wherein the radio waves could effectively destroy the core.

While only preferred embodiments and uses of this invention have been illustrated and described herein, it is to be understood that various modifications may be made in the fabric of this invention, as well as in the method ofmaking this fabric, as for example in making a fabric of several walls, all within the spirit and scope of the invention, as defined in the appended claims. I

We claim: i

l. The method of making a dual wall fabric comprising the steps of providing a dual-component strand material having components of different free lengths, with the longer component being wound about -a shorter core component, integrally weaving the fabric in opposed layers connected and closely spaced by integrally woven dual-component strands, and destructing the core components of shorter free length to release the wound strand components of greater free length to their fully extended lengths, whereby the original spacing between the fabric layers is free to increase.

2. The method of claim 1, wherein said destructing is effected by dissolving the core components of shorter free length in a bath of solvent subsequent to weaving the fabric.

3. The method of claim 1, wherein the weaving step includes weaving the dual-component connecting strand in the filling direction.

4. The method of claim 1, wherein the weaving step includes weaving the dual-component connecting strand in the warp direction.

5. The method of claim 2, wherein the solvent is water, including the step of heating the water.

6. The method of claim 1, wherein said destructing step comprises applying sufficient heat to the core components to render the core components susceptible of fracturing upon expansion of the spacing between the layers, with such heat being insufficient to destruct the wound strand components.

7. The method of claim 1, wherein said destructing step comprises dissolving the core components by applying a solvent thereto, with the material of the wound strand com- 7 8 onents having been predetermined to be substantially inert to is efl'ected as part of a continuous fabric making operation. the solvent, and with the material of the core components The fabric made according to the method of Claim being soluble in the solvent. l 1. The fabric made according to the method of claim 6.

8. The method of claim 7, wherein said solvent is water. The fabfiC made accmding to the method of claim 9. The method of claim 1, wherein the destructing operation 5 

1. The method of making a dual wall fabric comprising the steps of providing a dual-component strand material having components of different free lengths, with the longer component being wound about a shorter core component, integrally weaving the fabric in opposed layers connected and closely spaced by integrally woven dual-component strands, and destructing the core components of shorter free length to release the wound strand components of greater free length to their fully extended lengths, whereby the original spacing between the fabric layers is free to increase.
 2. The method of claim 1, wherein said destructing is effected by dissolving the core components of shorter free length in a bath of solvent subsequent to weaving the fabric.
 3. The method of claim 1, wherein the weaving step includes weaving the dual-component connecting strand in the filling direction.
 4. The method of claim 1, wherein the weaving step includes weaving the dual-component connecting strand in the warp direction.
 5. The method of claim 2, wherein the solvent is water, including the step of heating the water.
 6. The method of claim 1, wherein said destructing step comprises applying sufficient heat to the core components to render the core components susceptible of fracturing upon expansion of the spacing between the layers, with such heat being insufficient to destruct the wound strand components.
 7. The method of claim 1, wherein said destructing step comprises dissolving the core components by applying a solvent thereto, with the material of the wound strand components having been predetermined to be substantially inert to the solvent, and with the material of the core components being soluble in the solvent.
 8. The method of claim 7, wherein said solvent is water.
 9. The method of claim 1, wherein the destructing operation is effected as part of a continuous fabric making operation.
 10. The fabric made according to the method of claim
 1. 11. The fabric made according to the method of claim
 6. 12. The fabric made according to the method of claim
 7. 